Method for Producing a Sulfur Concrete Substance

ABSTRACT

A sulfur-containing material in a melt state is stored in material hopper heated to a temperature within a preset temperature range of which a lower limit is equal to or above a melting point of sulfur. The stored sulfur-containing material is sucked by pressure generators and pulled out into cylinders heated to a temperature within the preset temperature range. The pulled out sulfur-containing material is pushed out from the cylinders under pressure applied by the pressure generator, and thereafter, the resultant material is injected into mold heated to a temperature within the preset temperature range. An injection port of the mold after the sulfur-containing material is fully injected is closed. By stopping heating of the mold, the sulfur-containing material is slowly cooled. After that, a modified sulfur concrete substance formed by cooling and solidifying the sulfur-containing material is taken out from the mold.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. patent application Ser. No.12/891,575, filed on Sep. 27, 2010, which is a Continuation ofInternational Patent Application No. PCT/JP2009/055784, filed on Mar.24, 2009, which claims priority to foreign Patent Application No. JP2008-078240, filed on Mar. 25, 2008, the disclosures of which areincorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to a modified sulfur concrete substanceproducing method of forming a modified sulfur concrete substance byinjecting a sulfur-containing material in a melt state, underpredetermined pressure, into a mold having therein a cavity which can behermetically sealed and the mold being heated to a temperature within apreset temperature range, and thereafter, making the material in thecavity cooled and solidified, and to a producing apparatus used toexecute the method.

BACKGROUND OF THE INVENTION

Generally, concrete obtained by combining aggregate by cement is used asa civil-engineering material and construction material. The sulfurrecently receives an attention due to the characteristics that thesulfur is a solid at room temperature while melted upon being heated toabout 119° C. to 159° C., and it is attempted that the sulfur isutilized as a civil-engineering material and a construction material bymixing a predetermined sample or predetermined samples in it. It isknown that the sulfur-containing material using the sulfur has highstrength, an excellent water-sealing property and high acid resistance,as compared with usual concrete employing cement. Further, since thesulfur-containing material is apparently similar to a usual concrete infinishing and handling, sometimes the solidified material is calledsulfur concrete substance.

Since the sulfur has ignition property and is dealt with a hazardousmaterial, it is difficult to perform construction by melting, castingand solidifying the sulfur material on site. Therefore, in order toimprove such a situation, it is attempted that the sulfur is denaturedto produce modified sulfur by mixing a sulfur modifying agent as anadditive into molten sulfur. Further, it is attempted that a modifiedsulfur intermediate material in a melt state is produced by mixing themodified sulfur and fine powders, and a modified sulfur concretesubstance is produced by mixing the modified sulfur intermediatematerial with the aggregate and solidifying the mixture.

Further, in order to form the sulfur concrete substance or the modifiedsulfur concrete substance by making the sulfur-containing material (orthe modified sulfur intermediate material) in the melt state cooled andsolidified, the sulfur containing material is injected into a moldhaving a predetermined shape, and thereafter, is cooled and solidified.

As a technique of producing a sulfur-concrete product which can beimmediately removed from the mold after hermetic sealing and has asmooth surface and excellent durability, a technique is disclosed inwhich a mixture obtained by mixing from 1 to 20 volume parts of mineralfine powders to 1 volume part of the sulfur is heated to the meltingpoint of sulfur or higher and hermetically sealed, thereby forming acompact having self molding performance.

However, the sulfur-containing material in the melt state start tosolidify at the time point when the temperature is below solidificationtemperature (about 119° C.) of the sulfur and solidifies to have highstrength which is equal to or higher than that of usual concrete.Conventionally, when the sulfur-containing material in the melt statesolidifies, a part which is in contact with the mold when the materialis poured into the mold is cooled rapidly, so that a problem occurs suchthat the surface of the sulfur concrete substance or the modified sulfurconcrete substance removed from the mold is rough. In addition, it isdifficult to manufacture a product having high precision in shape.

Furthermore, when a cylindrical product such as a hume pipe or a manholeis manufactured by usual concrete, a producing method called centrifugalmolding of injecting the concrete into a cylindrical mold while rotatingand vibrating the mold so as to press the material against the innerperipheral surface of the mold by centrifugal force and vibration isemployed. In this case, a skilled hand is needed for finishing of theinner peripheral surface of the cylindrical product, and it takes longtime. First of all, since the sulfur-containing material in the meltstate start to solidify at the time point when the temperature is belowthe solidification temperature (about 119° C.) of the sulfur, a productmay not be manufactured by using the centrifugal molding of pressing thematerial against the inner peripheral surface of the mold by using thecentrifugal force.

SUMMARY OF THE INVENTION

In view of the above described problem, one aspect of the presentinvention provides a modified sulfur concrete substance producing methodof forming a modified sulfur concrete substance by injecting asulfur-containing material in a melt state, under predeterminedpressure, into a mold having therein a cavity of a predetermined shape,and thereafter, making the material in the cavity cooled and solidified,and a producing apparatus used to execute the method.

In order to achieve this aspect, a modified sulfur concrete substanceproducing method of an embodiment of the present invention includes: astep of storing a sulfur-containing material in a melt state in amaterial hopper heated to a temperature within a preset temperaturerange of which a lower limit is equal to or above a melting point ofsulfur; a step of sucking the sulfur-containing material stored in thematerial hopper by a pressure generator and pulling out thesulfur-containing material into a cylinder heated to a temperaturewithin the preset temperature range; a step of pushing out thesulfur-containing material pulled out into the cylinder, from thecylinder under a predetermined pressure applied by the pressuregenerator and injecting the sulfur-containing material from an injectionport of a mold, into the mold having therein a cavity which can behermetically sealed and the mold being heated to a temperature within apreset temperature range; a step of closing the injection port of themold after the sulfur-containing material is fully injected in thecavity; a step of slowly cooling the sulfur-containing material injectedin the cavity by stopping heating of the mold; and a step of taking outa modified sulfur concrete substance formed by cooling and solidifyingthe sulfur-containing material in the cavity, from the mold.

By the above-mentioned method, a sulfur-containing material in a meltstate is stored in a material hopper heated to a temperature within thepreset temperature range of which a lower limit is equal to or above themelting point of sulfur. The stored sulfur-containing material is suckedby pressure generators and pulled out into cylinders heated to atemperature within the preset temperature range. The pulled outsulfur-containing material is pushed out from the cylinder under thepredetermined pressure applied by the pressure generator to therebyinject the material from the injection port of the mold, into the moldhaving therein a cavity which can be hermetically sealed and the moldbeing heated to a temperature within the preset temperature range. Theinjection port of the mold is closed after the sulfur-containingmaterial is fully injected in the cavity. By stopping heating of themold, the sulfur-containing material injected in the cavity is slowlycooled, so that the modified sulfur concrete substance formed by coolingand solidifying the sulfur-containing material in the cavity is takenout from the mold. After that, the sulfur-containing material in themelt state is injected under the predetermined pressure into the moldhaving therein a cavity which can be hermetically sealed and the moldbeing heated to a temperature within the preset temperature range ofwhich a lower limit is equal to or above the melting point of sulfur,and thereafter, the material is cooled and solidified in the cavity,thereby forming a modified sulfur concrete substance. Therefore, even ifthe shape of a product made by the modified sulfur concrete substance iscomplicated, a product of high precision can be manufactured by theshape of the cavity in the mold. In addition, since the precision of theproduct is depend on the shape of the mold, regardless of the widenessof a finished surface of the mold and complication of the shape of themold, uniform products can be manufactured. Further, surface finishingof a product is not required, so that a skilled person is not needed.

The sulfur-containing material stored in the material hopper is agitatedby an agitating blade provided in the material hopper. By agitating thesulfur-containing material stored in the material hopper with theagitating blade, separation of the components is prevented, so that theuniform sulfur-containing material is injected to the mold. Therefore,intensity of solidification of the modified sulfur concrete substancecan be increased.

Further, in the step of injecting the sulfur-containing material intothe mold, the material is injected while applying vibration to the mold.By injecting the sulfur-containing material while applying vibration tothe mold, even if the sulfur-containing material is a material havinglow flowability, the material can be injected into the mold.

A modified sulfur concrete substance producing apparatus of anembodiment of the present invention includes: a material hopper heatedto a temperature within the preset temperature range of which a lowerlimit is equal to or above the melting point of sulfur, and which storesa sulfur-containing material in a melt state on the inside thereof; apressure generator which suck the sulfur-containing material stored inthe material hopper, pulls out the material into a cylinder heated to atemperature within the preset temperature range, and thereafter, pushesout the sulfur-containing material pulled out into the cylinder, fromthe cylinder under predetermined pressure; an opening and closing plateprovided at each of a pull port for pulling out the sulfur-containingmaterial in the material hopper into the cylinder and a push port forpushing out the sulfur-containing material from the cylinder, whichinterlockingly moves to alternately open and close the pull port and thepush port; an injection hose whose base end is connected to the pushport for the sulfur-containing material from the cylinder, the injectionhose being heated to a temperature within the preset temperature range,and in which the sulfur-containing material flows; a mold whoseinjection port of a sulfur-containing material is connected to the otherend of the injection hose, which has therein a cavity which iscommunicated with the injection port and also can be hermeticallysealed, which has an air-release hole communicated with the cavity, andthe mold being heated to a temperature within the preset temperaturerange; and an interrupting mechanism provided for the injection port inthe mold, which closes the injection port after the sulfur-containingmaterial is fully injected into the cavity.

With such a configuration, the sulfur-containing material in a meltstate heated to a temperature within the preset temperature range ofwhich a lower limit is equal to or above the melting point of sulfur isstored on the inside of the material hopper. By the pressure generator,the sulfur-containing material stored in the material hopper is suckedand pulled out into a cylinder heated to a temperature within the presettemperature range. The sulfur-containing material pulled out into thecylinder is pushed out from the cylinder under the predeterminedpressure. By the opening and closing plates provided at each of the pullport for pulling out the sulfur-containing material in the materialhopper into the cylinder and the push port for pushing out thesulfur-containing material from the cylinder, which interlockinglymoves, so that the pull port and the push port are alternately openedand closed. The injection hose is heated to a temperature within thepreset temperature range and the sulfur-containing material flowstherein, the base end of the injection hose is connected to the pushport for the sulfur-containing material from the cylinder. The other endof the injection hose is connected to the injection port for thesulfur-containing material of the mold having therein a cavity which iscommunicated with the injection port and can be hermetically sealed,having an air-release hole communicated with the cavity, and the moldbeing heated to a temperature within the preset temperature range. Bythe interrupting mechanism provided for the injection port, theinjection port of the mold is closed after the sulfur-containingmaterial is fully injected into the cavity. With such a configuration, asulfur-containing material in a melt state is injected underpredetermined pressure into the mold having therein a cavity which canbe hermetically sealed, and the mold being heated to a temperaturewithin the preset temperature range of which a lower limit is equal toor above a melting point of sulfur. After that, the sulfur-containingmaterial is cooled and solidified in the cavity, thereby forming amodified sulfur concrete substance. Therefore, even if the shape of aproduct made by the modified sulfur concrete substance is complicated, aproduct of high precision can be manufactured by the shape of the cavityin the mold. Further, since the precision of the product is depend onthe shape of the mold, regardless of the wideness of the finishedsurface of the mold and the complication of the shape of the mold,uniform products can be manufactured. Furthermore, the surface finishingof a product is not required, so that a skilled person is not needed.

Each of the material hopper, the cylinder of the pressure generator, theinjection hose, and the mold is provided with heating means so as to beheated to a temperature within the preset temperature range of which alower limit is equal to or above a melting point of sulfur. With theconfiguration, by the heating means provided for each of the materialhopper, the cylinder of the pressure generator, the injection hose, andthe mold, each of the components is heated to a temperature within thepreset temperature range of which a lower limit is equal to or above amelting point of the sulfur material. Therefore, the sulfur-containingmaterial can be maintained in a melt state on the inside of each of thecomponents.

Further, each of the periphery of the material hopper, the cylinder ofthe pressure generator, the injection hose, and the mold is covered witha box-shaped member to increase atmospheric temperature in thebox-shaped member so as to heat each of the components to a temperaturewithin the preset temperature range of which a lower limit is equal toor above a melting point of the sulfur material. With the configuration,by surrounding the periphery of the material hopper, the cylinder of thepressure generator, the injection hose, and the mold with a box-shapedmember and increasing atmospheric temperature in the box-shaped member,each of the components is heated to a temperature within the presettemperature range of which a lower limit is equal to or above themelting point of sulfur. Therefore, in each of the components, thesulfur-containing material can be maintained in a melt state.

Further, a plurality of pressure generators is provided in parallel tothe material hopper, alternately executes operation of sucking thesulfur-containing material stored in the material hopper and pulling outit into the cylinder and an operation of pushing out thesulfur-containing material pulled out into the cylinder, from thecylinder under predetermined pressure. By the plurality of pressuregenerators provided in parallel to the material hopper, the operation ofsucking the sulfur-containing material stored in the material hopper andpulling out it into the cylinder and the operation of pushing out thesulfur-containing material pulled out into the cylinder, from thecylinder under predetermined pressure can be executed alternately.Therefore, in the case where the number of the pressure generators istwo (two cylinders), the operation of pulling out the sulfur-containingmaterial from the material hopper into the cylinder and the operation ofpushing out the sulfur-containing material from the cylinder can beexecuted simultaneously, so that the time for injecting thesulfur-containing material to the mold can be shortened.

The opening and closing plate is housed in a plate cover as a casingcovering the periphery of the opening and closing plate in thelongitudinal direction except for portions of a pull port for pullingout the sulfur-containing material from the material hopper and a pushport for pushing out the sulfur-containing material from the cylinder,and the opening and closing plate slides in the plate cover. With theconfiguration, the opening and closing plate housed in the plate coveras the casing covering the periphery of the opening and closing plate inthe longitudinal direction, slides in the plate cover, therebypreventing the sulfur-containing material remaining in the portions ofthe pull port for the sulfur-containing material from material hopperand the push port for the sulfur-containing material from the cylinderfrom spilling over in the periphery. Therefore, the sulfur-containingmaterial can be prevented from being adhered and solidified in theopening and closing plate and in the vicinity of a lower part of thematerial hopper, so that the maintenance can be facilitated.

Further, the cylinder of the pressure generator has a structure whichcan be divided into upper and lower parts along the longitudinaldirection thereof. With the structure, at the time of maintenance, thecylinder of the pressure generator can be divided into the upper andlower parts along the longitudinal direction. Therefore, the maintenancecan be facilitated.

Further, an agitating blade for agitating the sulfur-containing materialstored in the material hopper is provided on the inside of the materialhopper. By agitating the sulfur-containing material stored in thematerial hopper with the agitating blade provided on the inside of thematerial hopper, separation of the components is prevented, so that theuniform sulfur-containing material is injected to the mold. Therefore,intensity of solidification of the modified sulfur concrete substancecan be increased.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating an embodiment of a modifiedsulfur concrete substance producing apparatus according to the presentinvention.

FIG. 2 is an enlarged front view of a material hopper illustrated inFIG. 1.

FIG. 3 is an enlarged side view of the material hopper illustrated inFIG. 1.

FIG. 4 is an enlarged plan view of a pressure generator illustrated inFIG. 1.

FIG. 5 is an exploded perspective view illustrating components of a moldillustrated in FIG. 1.

FIG. 6 is an exploded perspective view illustrating the structure of themold illustrated in FIG. 1.

FIG. 7 is a perspective explanatory view illustrating a state where anupper half of a cylinder is exploded, for explaining operation of thepressure generator and an opening and closing plate illustrated in FIG.1.

FIG. 8 is similarly a perspective explanatory view illustrating a statewhere an upper half of a cylinder is exploded, for explaining operationof the pressure generator and the opening and closing plate shown inFIG. 1.

FIG. 9 is a transverse cross section view illustrating a planeorthogonal to the longitudinal direction of a mold, at a position of aninjection port, for explaining a mechanism of interrupting the injectionport of the mold.

FIG. 10 is similarly a transverse cross section view illustrating aplane orthogonal to the longitudinal direction of a mold, at a positionof an injection port of the mold.

FIG. 11 is similarly a transverse cross section view illustrating aplane orthogonal to the longitudinal direction of a mold, at a positionof an injection port of the mold.

FIG. 12 is a perspective view illustrating a mechanism of interruptingthe injection port of the mold.

FIG. 13 is similarly a perspective view illustrating a mechanism ofinterrupting the injection port of the mold.

DETAILED DESCRIPTION

Preferred embodiments of the present invention will be described indetail with reference to the accompanying drawings.

FIG. 1 is a perspective view illustrating an embodiment of a modifiedsulfur concrete substance producing apparatus according to the presentinvention. The apparatus is used for executing a modified sulfurconcrete substance producing method of forming a modified sulfurconcrete substance by injecting a sulfur-containing material in a meltstate, under predetermined pressure, into a mold having therein a cavitywhich can be hermetically sealed and the mold being heated to atemperature within a preset temperature range of which a lower limit isequal to or above a melting point of sulfur, and thereafter, making thematerial in the cavity cooled and solidified, thereby forming a modifiedsulfur concrete substance. The apparatus has a material hopper 1,pressure generators 2 a and 2 b, opening and closing plates 3 a and 3 b,an injection hose 4, a mold 5, and an interrupting mechanism 6 (refer toFIG. 9).

Material hopper 1 stores a sulfur-containing material in a melt state onthe inside. As illustrated in FIGS. 2 and 3, material hopper 1 is madeof a metal and formed in a funnel shape, and the volume of materialhopper 1 is, for example, about 1.0 m³. The peripheral portion ofmaterial hopper 1 is provided with heating means such as an electricheater, a hot-air heater, or an oil heater and is covered with a heatinsulating material. Material hopper 1 is heated to a temperature withinthe preset temperature range of which a lower limit is equal to or abovethe melting point (119° C.) of sulfur. The preset temperature range ofheating is, preferably, about 135 to 150° C. In the range, thesulfur-containing material in the melt state stored in material hopper 1is held in the melt state without solidifying.

Material hopper 1 has therein agitating blades 7 a and 7 b. Agitatingblades 7 a and 7 b agitate the sulfur-containing material stored inmaterial hopper 1 and, as illustrated in FIGS. 2 and 3, are attached atboth ends of an arm shaft 10 orthogonal to a rotary shaft 9 extendingtoward a downward direction from a rotation driving source 8 such as anelectric motor disposed on the top face of material hopper 1. Byrotating agitating blades 7 a and 7 b by driving rotation driving source8, the sulfur-containing material stored in material hopper 1 isagitated and, without separation of the materials, the uniformsulfur-containing material can be injected into mold 5 which isdescribed later. Further, by setting the mounting angle of agitatingblades 7 a and 7 b so that agitating blades 7 a and 7 b are twisteddownward like propeller blades, the sulfur-containing material stored inmaterial hopper 1 can be sent downward while being agitated.

The sulfur-containing material is explained below. The sulfur-containingmaterial is called a sulfur concrete substance produced by, using thecharacteristics that the sulfur is solid at room temperature whilemelted upon being heated to about 119 to 159° C., mixing sands, gravels,coal ashes or the like with the sulfur melted by being heated to atemperature within the preset temperature range of which a lower limitis equal to or above 119° C. and kneading the mixed material whilemaintaining the temperature at about 119 to 159° C., and thereafter,cooling and hardening the kneaded material. The sulfur-containingmaterial may be called a modified sulfur concrete substance produced bymixing the sulfur melted by being similarly heated to a temperaturewithin the preset temperature range of which a lower limit is equal toor above 119° C. with a sulfur modifying agent which denatures themelted sulfur to produce modified sulfur, and mixing sands, gravels,coal ashes or the like with the modified sulfur, and kneading the mixedmaterial by being heated in a manner similar to the above, andthereafter, cooling and hardening the knead material. That is, thesulfur-containing material includes the sulfur concrete substance andthe modified sulfur concrete substance. As used herein, the term“modified sulfur concrete substance” intends to include, but not limitedto, “sulfur concrete substance”.

The modified sulfur concrete substance is further described in detail.The modified sulfur concrete substance is produced by using sulfur, asulfur modifying agent, fine powders, and aggregate as materials. First,the melted sulfur and the sulfur modifying agent are mixed to producethe modified sulfur. Sulfur is usual simple sulfur and is, for example,natural sulfur or sulfur produced by desulfurizing petroleum or naturalgas. The sulfur modifier performs modification by denaturing the meltedsulfur, for example, polymerizing sulfur. The sulfur modifying agent maybe any compound which can polymerize sulfur. For example, the sulfurmodifier is olefinic hydrocarbon or diolefin hydrocarbon having carbonnumber of from 4 to 20, concretely, the sulfur modifier is one of acyclic olefinic hydrocarbon such as limonene or pinene, aromatichydrocarbon such as styrene, vinyl toluene, or methylstyrene, and dienehydrocarbon such as dicyclopentadiene (DCPD) and its oligomer,cyclopentadiene, tetrahydroindene (THI), vinylcyclohexene,vinylnorbornene, ethylidene norbornene, or cyclooctadiene, or a mixtureof two or more of the hydrocarbons. The sulfur and the sulfur modifyingagent are mixed in a state where sulfur is melted, that is, at atemperature range from 119 to 159° C., preferably, from 135 to 150° C.

The modified sulfur can be obtained by melt-mixing the sulfur withsulfur modifying agent. The percent of use of the sulfur modifying agentin this case is, preferably, from 0.1 to 30 percent by mass, morepreferably, from 1.0 to 20 percent by mass to the total amount of sulfurand the sulfur modifying agent. The obtained modified sulfur is mixedwith fine powders heated to a predetermined temperature (for example,150° C.), thereby obtaining a modified sulfur intermediate material. Asthe fine powders, one or more of coal ash, siliceous, silica fume, glasspowders, fuel incineration, electrically collected dust and crushed seashell may be selected.

The obtained modified sulfur intermediate material is mixed with theaggregate heated to, for example, about from 130 to 140° C. in a statewhere the temperature is maintained at a temperature at which a meltstate can be maintained (for example, from 130 to 140° C.). Theaggregate is not limited as long as it can be used as aggregate, andaggregate generally used for concrete can be used. Examples of suchaggregate are one or more materials selected from the group of naturalstones, sands, gravels, siliceous, iron and steel slag, ferronickelslag, copper slag, side product generated at the time of manufacturing ametal, liquid slags, shells and a mixture of the materials. By mixingthe modified sulfur intermediate material and the aggregate by using,for example, a kneading unit, the modified sulfur material is produced,and thereafter, by cooling and solidifying the modified sulfur material,a modified sulfur concrete substance is produced. Such a modified sulfurconcrete substance can be produced by using, for example, a modifiedsulfur concrete substance producing system.

In the following description, such a sulfur concrete substance or amodified sulfur concrete substance is heated in the preset temperaturerange, and the resultant is used as a sulfur-containing material in amelt state.

In FIG. 1, below material hopper 1, pressure generators 2 a and 2 b areprovided. Pressure generators 2 a and 2 b are used to suck thesulfur-containing material stored in material hopper 1 and push out thesucked sulfur-containing material under predetermined pressure.Reference numeral 2 a denotes a first pressure generator, and referencenumeral 2 b denotes a second pressure generator. As illustrated in FIG.7, first pressure generator 2 a includes a cylinder 11 a having acylindrical shape, a piston 12 a fit in cylinder 11 a, a piston rod 13 afor pushing/pulling piston 12 a, and a driving motor 14 a such as anelectric motor for making piston rod 13 a elongate and contract.Similarly, second pressure generator 2 b includes a cylinder 11 b havinga cylindrical shape, a piston 12 b fit in cylinder 11 b, a piston rod 13b for pushing/pulling piston 12 b, and a driving motor 14 b such as anelectric motor for making piston rod 13 b elongate and contract.

As for dimensions of each of cylinders 11 a and 11 b, for example, theinside diameter is 130 mm, and a stroke is 600 mm. The pushed out amountof the sulfur-containing material per one time is 7.96L. A predeterminedpressure at the time of pushing out the sulfur-containing material is,for example, 98 kPa (about 1 kg/cm²) or higher and 147 kPa (about 1.5kg/cm²) or 196 kPa (about 2.0 kg/cm²) or less. Driving motors 14 a and14 b may be hydraulic motors.

As illustrated in FIG. 1, the above-mentioned pressure generators 2 aand 2 b are provided in parallel to the horizontal direction to materialhopper 1 (refer to FIG. 4), and can alternately perform operation ofsucking a sulfur-containing material stored in material hopper 1 andpulling it out into cylinders 11 a and 11 b and operation of pushingout, from cylinders 11 a and 11 b, the sulfur-containing material pulledout into cylinders 11 a and 11 b under the predetermined pressure.

The peripheral portion of each of cylinders 11 a and 11 b of pressuregenerators 2 a and 2 b is provided with heating means such as anelectric heater, a hot-air heater, or an oil heater and is covered witha heat insulating material. Cylinders 11 a and 11 b are heated to atemperature within a preset temperature range of which a lower limit isequal to or above the melting point (119° C.) of sulfur (for example,about from 135 to 150° C.). In the range, the sulfur-containing materialin the melt state, which is pulled out into cylinders 11 a and 11 b, isheld in the melt state without solidifying.

Each of cylinders 11 a and 11 b of pressure generators 2 a and 2 b has astructure which can be divided into upper and lower parts along thelongitudinal direction thereof, as shown in FIGS. 7 and 8. For example,the cylindrical member is formed in a shape which can be divided intotwo upper and lower half cylindrical members along the longitudinaldirection, which are fastened by bolts, nuts, or the like. With thestructure, at the time of maintenance, each of cylinders 11 a and 11 bof pressure generators 2 a and 2 b is divided into the two upper andlower parts along the longitudinal direction to clean the inside.Consequently, maintenance can be facilitated.

In a portion where cylinders 11 a and 11 b of pressure generators 2 aand 2 b are coupled to the lower part of material hopper 1, opening andclosing plates 3 a and 3 b are provided, as illustrated in FIG. 1.Opening and closing plates 3 a and 3 b alternately open and close pullports 15 a and 15 b for pulling out the sulfur-containing material inmaterial hopper 1 into cylinders 11 a and 11 b and push ports 16 a and16 b for pushing out the sulfur-containing material from cylinders 11 aand 11 b. Opening and closing plates 3 a and 3 b are provided for pullports 15 a and 15 b and push ports 16 a and 16 b, respectively. The twoopening and closing plates interlockingly move.

Specifically, pull ports 15 a and 15 b for the sulfur-containingmaterial are formed so as to be adapted to the interval betweencylinders 11 a and 11 b of pressure generators 2 a and 2 b at the lowerpart of material hopper 1. Push ports 16 a and 16 b for thesulfur-containing material are formed so as to be adapted to theinterval between cylinders 11 a and 11 b at the front end side (refer toFIG. 3) of cylinders 11 a and 11 b of pressure generators 2 a and 2 b.As illustrated in FIGS. 2 to 4, each of opening and closing plates 3 aand 3 b is formed as a member having an elongated plate shape, thelength thereof is at least twice of the interval between cylinders 11 aand 11 b. Further, opening and closing plates 3 a and 3 b can move in adirection orthogonal to the longitudinal direction of cylinders 11 a and11 b. The opening and closing plate which opens and closes pull ports 15a and 15 b is set as first opening and closing plate 3 a which isdisposed so that, in FIG. 3, the plane thereof is positioned in ahorizontal plane at the lower part of material hopper 1. The opening andclosing plate which opens and closes push ports 16 a and 16 b is set assecond opening and closing plate 3 b which is disposed so that, in FIG.3, the plane thereof is positioned in a vertical plane at the front endof each of cylinders 11 a and 11 b of pressure generators 2 a and 2 b.

In first opening and closing plate 3 a, as illustrated in FIG. 4, onethrough hole 17 is provided, for example, at a center portion in thelongitudinal direction. When first opening and closing plate 3 a movesin the directions of the arrows A and B, through hole 17 matches eitherpull port 15 a or 15 b to thereby alternately open or close two pullports 15 a and 15 b. In second opening and closing plate 3 b, asillustrated in FIG. 2, through holes 18 a and 18 b are provided, forexample, at both ends in the longitudinal direction. When second openingand closing plate 3 b moves in the directions of the arrows A and B,through hole 18 a as one of the through holes matches one push port 16 ato close the other push port 16 b in an almost center portion of openingand closing plate 3 b. When the other through hole 18 b matches theother push port 16 b, push port 16 a is closed in an almost centerportion of opening and closing plate 3 b. In such a manner, two pushports 16 a and 16 b are alternately opened and closed.

In such a state, one end (right end in FIGS. 1 and 2) of each of firstand second opening and closing plates 3 a and 3 b is connected to an endplate 19 having a rectangular shape. An extensible rod 20 is coupled toend plate 19, and a drive cylinder 21 such as an air cylinder is mountedat one end of extensible rod 20. By making extensible rod 20 elongate orcontract in the direction of arrow A or B by driving drive cylinder 21,first and second opening and closing plates 3 a and 3 b moveinterlockingly in the directions of arrows A and B. As a result, usingfirst and second opening and closing plates 3 a and 3 b, pull ports 15 aand 15 b and push ports 16 a and 16 b can be alternately opened andclosed. In this case, one drive cylinder 21 and one extensible rod 20are sufficient, so that the structure and operation are simplified.

As illustrated in FIGS. 1 and 8, first and second opening and closingplates 3 a and 3 b are housed in plate covers 22 a and 22 b as casingscovering the periphery of plates in the longitudinal direction exceptfor the portion of pull ports 15 a and 15 b for the sulfur-containingmaterial from material hopper 1 and push ports 16 a and 16 b for thesulfur-containing material from cylinders 11 a and 11 b, and slide inplate covers 22 a and 22 b. That is, first and second opening andclosing plates 3 a and 3 b are inserted in plate covers 22 a and 22 b ascasings and slide interlockingly in the directions of arrows A and B,thereby preventing the sulfur-containing material remaining in theportion of pull ports 15 a and 15 b for the sulfur-containing materialfrom material hopper 1 and push ports 16 a and 16 b for thesulfur-containing material from cylinders 11 a and 11 b from spillingover in the periphery.

As illustrated in FIGS. 1 and 4, a material introduction pipe 23 havinga fork shape is coupled to push ports 16 a and 16 b for thesulfur-containing material from cylinders 11 a and 11 b. At one end 23 aof material introduction pipe 23, the sulfur-containing material iscombined to one pipe and led to injection hose 4 described later.

To push ports 16 a and 16 b for the sulfur-containing material fromcylinders 11 a and 11 b, the base end portion of injection hose 4 isconnected. Injection hose 4 is provided to inject the sulfur-containingmaterial in the melt state pushed out from push ports 16 a and 16 b forthe sulfur-containing material from cylinders 11 a and 11 b to mold 5described later. Injection hose 4 is made of a material having heatresistance within the preset temperature range of which a lower limit isequal to or above the melting point of sulfur (about from 135 to 150°C.) and having flexibility. Injection hose 4 is connected to one end 23a of material introduction pipe 23.

The peripheral portion of injection hose 4 is provided with heatingmeans such as an electric heater, a hot-air heater, or an oil heater andis covered with a heat insulating material. Injection hose 4 is heatedto a temperature within the preset temperature range of which a lowerlimit is equal to or above the melting point (119° C.) of sulfur (forexample, about from 135 to 150° C.), so that the sulfur-containingmaterial in the melt state led into injection hose 4 is maintained inthe melt state without solidifying and flows in injection hose 4.

To the other end of injection hose 4, an injection port 24 of thesulfur-containing material of mold 5 is connected. Mold 5 forms themodified sulfur concrete substance by injecting the sulfur-containingmaterial in the melt state thereinto under the predetermined pressure,and thereafter, making the material cooled and solidified. Mold 5 ismade of a metal such as steel or aluminum and is formed in a shapeadapted to the shape of a modified sulfur concrete substance product tobe manufactured. For example, mold 5 illustrated in FIG. 1 is used tomanufacture a cylindrical modified sulfur concrete substance productsuch as a Hume pipe or manhole.

A concrete structure of mold 5 is described with reference to FIGS. 5and 6. FIG. 5 is an exploded perspective view illustrating thecomponents of mold 5 illustrated in FIG. 1. Mold 5 has a cavity which iscommunicated with injection port 24 and can be hermetically sealed, andhas an air-release hole communicated with the cavity. Mold 5 is heatedto a temperature within the preset temperature range, and has an innermold 25, outer molds 26 a and 26 b as two members, and two end planks 27a and 27 b.

Inner mold 25 specifies the inner peripheral surface of a cylindricalproduct to be manufactured and is made by a member whose outerperipheral surface is formed in a columnar shape with predeterminedlength. By moving a part 25 a of the member extending in thelongitudinal direction to the inside, entire inner mold 25 can benarrowed to the inside. Outer molds 26 a and 26 b specify the outerperipheral surface of the cylindrical product to be manufactured. Eachof outer molds 26 a and 26 b is made by a member having an insidediameter larger than the outside diameter of inner mold 25 and formed ina cylindrical shape with predetermined length. Outer molds 26 a and 26 bcan be divided into two half cylindrical members along the longitudinaldirection. They may be divided into three or more members. Further, endplanks 27 a and 27 b specify both end faces of the cylindrical productto be manufactured. Each of end planks 27 a and 27 b is formed in adonut shape or a circular plate shape having the outside diameter largerthan that of each of outer molds 26 a and 26 b. End planks 27 a and 27 bare disposed at both ends of inner mold 25 and outer molds 26 a and 26b.

As illustrated in FIG. 6, inner mold 25 whose outer peripheral surfaceis formed in a columnar shape is covered with outer molds 26 a and 26 bas two half cylindrical members. Inner mold 25 and outer molds 26 a and26 b are combined in a cylindrical shape by bolts, nuts or the like. Twoend planks 27 a and 27 b are disposed at both ends of outer molds 26 aand 26 b. Both ends of inner mold 25 are fit in center openings of donutplate shapes of end planks 27 a and 27 b, and end planks 27 a and 27 bare fixed to outer molds 26 a and 26 b by bolts, nuts or the like. Insuch a manner, mold 5 illustrated in FIG. 1 is assembled.

In this state, in a space surrounded by inner mold 25, outer molds 26 aand 26 b, and end planks 27 a and 27 b, a cavity 28 (refer to FIG. 9)which is communicated with injection port 24 and can be hermeticallysealed is formed. In the top face of outer mold 26 a as one of outermolds, an air-release hole 29 in a pipe shape for letting air releasewhen a sulfur-containing material in a melt state is injected frominjection port 24 into cavity 28 is provided.

The peripheral portion of outer molds 26 a and 26 b is provided withheating means such as an electric heater, a hot-air heater, or an oilheater and is covered with a heat insulating material. Outer molds 26 aand 26 b are heated to a temperature within the preset temperature rangeof which a lower limit is equal to or above the melting point (119° C.)of sulfur (for example, about from 135 to 150° C.). In the range, thesulfur-containing material injected in outer molds 26 a and 26 b ismaintained in the melt state without solidifying, and is spread toentire cavity 28 surrounded by inner mold 25, outer molds 26 a and 26 b,and end planks 27 a and 27 b.

Mold 5 illustrated in FIGS. 1, 5, and 6 shows a mold shape in the caseof manufacturing a cylindrical product by a modified sulfur concretesubstance. In the case of manufacturing a product having a shape otherthan the cylindrical shape, shapes of inner mold 25, outer molds 26 aand 26 b, and end planks 27 a and 27 b may be determine in accordancewith the shape of the product. When the product shape is not a pipeshape but is a plate shape, a board shape, a block shape or the like,inner mold 25 may be unnecessary.

As illustrated in FIGS. 9 to 11, injection port 24 of mold 5 is providedwith interrupting mechanism 6. FIGS. 9 to 11 are transverse crosssection views each illustrating a plane orthogonal to the longitudinaldirection of mold 5, in a position of injection port 24. Interruptingmechanism 6 closes injection port 24 after the sulfur-containingmaterial is fully injected into cavity 28 via injection hose 4. In FIG.9, at a position in front of injection port 24 of mold 5, an injectionport opening/closing plate 30 is provided to slidably move up and down.As illustrated in FIG. 12, a guide plate 31 having hook-shaped retainerson both sides thereof is fixed in the front position of injection port24 of mold 5, both sides of injection port opening/closing plate 30 areretained by the retainers of guide plate 31, so that injection portopening/closing plate 30 slidably moves up and down.

In FIGS. 9 and 12, a hose hook 32 for connecting the other end ofinjection hose 4 is attached to a lower part of injection portopening/closing plate 30. In an upper part of injection portopening/closing plate 30, a port cap 33 for closing injection port 24 ofmold 5 illustrated in FIG. 9 is provided so that it can move forward orbackward. In injection port opening/closing plate 30, in positions wherehose hook 32 and port cap 33 are attached, through holes (refer to FIG.9) matched and communicated with injection port 24 of mold 5 areprovided. Port cap 33 is supported on the inside of an attachmentfitting 34 whose side sectional shape is a U shape, and is attached atthe tip of a push-in bolt 36. By rotating push-in bolt 36 in a forwardor reverse direction to a nut 35 fixed to attachment fitting 34, portcap 33 can move forward or backward. The transverse sectional shape ofport cap 33 is the same as that of injection port 24.

In FIG. 9, reference numeral 37 denotes a reinforcement flange attachedto the inner peripheral face of inner mold 25. Reference numeral 38denotes a notch formed in flange 37 as a clearance used at the time ofnarrowing entire inner mold 25 to the inside by moving a part 25 a ofinner mold 25 to the inside. Reference numeral 39 denotes areinforcement flange attached to the outer peripheral surface of outermolds 26 a and 26 b. Reference numeral 40 denotes a coupling bolt usedfor separating outer molds 26 a and 26 b to two half cylindrical membersalong the longitudinal direction or coupling outer molds 26 a and 26 b.

A state of closing injection port 24 of mold 5 by using interruptingmechanism 6 having the above configuration is described. FIG. 9illustrates a state where the sulfur-containing material is to beinjected in cavity 28 of mold 5. Injection port opening/closing plate 30is moved upward along guide plate 31, so that the position of hose hook32 matches the position of injection port 24 of mold 5. In this state,the other end of injection hose 4 illustrated in FIG. 1 is connected tohose hook 32 to inject a sulfur-containing material in a melt state frominjection port 24 of mold 5 into cavity 28.

After the sulfur-containing material is fully injected in cavity 28, asillustrated in FIG. 10, injection port opening/closing plate 30 is moveddownward as indicated by arrow C along guide plate 31 to make theposition of port cap 33 match with that of injection port 24 of mold 5.In this state, as illustrated in FIG. 11, push-in bolt 36 is rotated inthe forward direction to move forward as indicated by arrow D to therebypush port cap 33 in injection port 24 of mold 5. At this time, in FIG.10, the sulfur containing material remaining in injection port 24 ispushed into cavity 28 by the push-in of port cap 33. Consequently,finishing of a portion corresponding to injection port 24 in themodified sulfur concrete substance product formed by cooling andsolidifying in cavity 28 is facilitated, and the portion can be finishedas a smooth plane.

The operation of the modified sulfur concrete substance producingapparatus constructed as described above and the method of producing themodified sulfur concrete substance is described. First, in FIG. 1, thesulfur-containing material in the melt state is stored in materialhopper 1 heated to a temperature within a preset temperature range ofwhich a lower limit is equal to or above the melting point (119° C.) ofsulfur (for example, about from 135 to 150° C.). The sulfur-containingmaterial stored in material hopper 1 may be agitated by agitating blades7 a and 7 b provided in material hopper 1.

The sulfur-containing material stored in material hopper 1 is sucked bysecond pressure generator 2 b to be pulled into cylinder 11 b heated tothe preset temperature range, and also, the sulfur-containing materialalready pulled in another cylinder 11 a is pushed out from cylinder 11 aunder predetermined pressure applied by first pressure generator 2 a andinjected from injection port 24 into mold 5 having therein cavity 28which can be hermetically sealed and the mold being heated to the presettemperature range.

As illustrated in FIG. 7, extensible rod 20 extends in the direction ofarrow A by driving drive cylinder 21, so that through hole 17 in firstopening and closing plate 3 a matches pull port 15 b (refer to FIG. 1)from material hopper 1 to be opened, and further, through hole 18 a insecond opening and closing plate 3 b matches push port 16 a (refer toFIG. 1) from cylinder 11 a to be opened. By the operation of opening andclosing plates 3 a and 3 b and the operation of first and secondpressure generators 2 a and 2 b, the sulfur-containing material storedin material hopper 1 is pulled into cylinder 11 b, and thesulfur-containing material already pulled in another cylinder 11 a ispushed out and injected from injection port 24 into mold 5.

After the above-mentioned process, as illustrated in FIG. 8, extensiblerod 20 is contracted in the direction of arrow B by driving drivecylinder 21, so that through hole 17 in first opening and closing plate3 a matches pull port 15 a (refer to FIG. 1) from material hopper 1 andto be opened and further, through hole 18 b in second opening andclosing plate 3 b matches push port 16 b (refer to FIG. 1) from cylinder11 b of second pressure generator 2 b to be opened. By the operation ofopening and closing plates 3 a and 3 b and the operation of first andsecond pressure generators 2 a and 2 b, the sulfur-containing materialstored in material hopper 1 is pulled into cylinder 11 a of firstpressure generator 2 a, and the sulfur-containing material pulled incylinder 11 b of second pressure generator 2 b last time is pushed outand injected from injection port 24 into mold 5. After that, theoperation is repeated.

The sulfur-containing material is injected to mold 5 by, as illustratedin FIG. 1, connecting the base end of injection hose 4 to one end 23 aof material introduction pipe 23 coupled to push ports 16 a and 16 b forthe sulfur-containing material from cylinders 11 a and 11 b, andconnecting the other end of injection hose 4 to injection port 24 ofmold 5. Injection hose 4 is connected to mold 5 by, as illustrated inFIG. 9, being connected to hose hook 32 attached to a lower part ofinjection port opening/closing plate 30 provided at the front positionof injection port 24 of mold 5. When the sulfur-containing material isinjected into mold 5, air in mold 5 escapes from air-release hole 29provided in the top face of outer mold 26 a.

While the sulfur-containing material is injected into mold 5, materialhopper 1, cylinders 11 a and 11 b of pressure generators 2 a and 2 b,injection hose 4 and mold 5 are heated to a temperature within a presettemperature range of which a lower limit is equal to or above themelting point (119° C.) of sulfur (for example, about from 135 to 150°C.). Consequently, the sulfur-containing material is not solidified butcan be maintained in the melt state in each of the components. In theprocess of injecting the sulfur-containing material into mold 5, thematerial may be injected while applying vibrations to mold 5. In thiscase, even if the sulfur-containing material is a material having lowflowability, the material can be injected into mold 5.

After the sulfur-containing material is fully injected in cavity 28 ofmold 5, injection port 24 of mold 5 is closed. The operation of closinginjection port 24 is performed by pushing port cap 33 into injectionport 24 of mold 5 by using interrupting mechanism 6 illustrated in FIGS.9 to 11. By the push-in of port cap 33, the sulfur-containing materialremaining in injection port 24 is pushed against cavity 28, so that thepart corresponding to injection port 24 can be finished as a smoothsurface.

After that, injection hose 4 is detached from injection port 24 of mold5, and is connected to injection port 24 of another mold 5 formanufacturing the next product.

In this state, heating of mold 5 is stopped, and the sulfur-containingmaterial injected in cavity 28 is slowly cooled at room temperature.After a predetermined time is elapsed, as illustrated in FIG. 5, mold 5is disassembled, and the modified sulfur concrete substance formed bycooling and solidifying the sulfur-containing material in cavity 28 istaken out from mold 5. Mold 5 is disassembled as follows. By moving apart 25 a of inner mold 25 to the inside in FIG. 9, entire inner mold 25is narrowed to the inside and separated from the modified sulfurconcrete substance. Inner mold 25 is pulled out by using a dedicatedjig. After that, end planks 27 a and 27 b at both ends are separatedfrom the modified sulfur concrete substance. Finally, outer molds 26 aand 26 b are divided into two upper and lower members. In such a manner,the modified sulfur concrete substance as a product can be taken outfrom mold 5.

In the above description, two pressure generators 2 (2 a and 2 b) areprovided in parallel to material hopper 1, which suck thesulfur-containing material stored in material hopper 1, pull it out intocylinder 11 heated to a temperature within the preset temperature range,and push out the sulfur-containing material pulled in cylinder 11 fromcylinder 11 by applying the predetermined pressure to the material. Thepresent invention is not limited to the arrangement, namely, only onepressure generator may be provided for material hopper 1. In this case,the operation of sucking the sulfur-containing material stored inmaterial hopper 1 and pulling it out into cylinder 11 and the operationof pushing the sulfur-containing material pulled in cylinder 11 fromcylinder 11 under predetermined pressure cannot be executed alternately.However, the basic operations can be similarly executed, and thestructure can be simplified.

In the above description, in order to heat each of material hopper 1,cylinders 11 a and 11 b of pressure generators 2 a and 2 b, injectionhose 4, and mold 5 to a temperature within a preset temperature range ofwhich a lower limit is equal to or above the melting point of sulfur,heating means is provided for each of the components thereof. However,the present invention is not limited to the above, as illustrated inFIG. 1, it is also possible to surround the periphery of the componentswith box-shaped members 40, 41 and the like, and transmit heated air inthe preset temperature range (for example, about from 135 to 150° C.) bya heated air supplying apparatus such as a jet heater, to the inside ofeach of the members 40, 41 and the like so as to increase theatmospheric temperature in the members 40, 41 and the like to themelting point (119° C.) of sulfur or higher. In this case, it issufficient to only surround the periphery of each of the components bythe box-shaped member 40, 41 or the like. Therefore, existing materialhopper 1, cylinders 11 a and 11 b of pressure generators 2 a and 2 b,injection hose 4, and mold 5 can be used. Accordingly, it is alsopossible to shift to the producing of the modified sulfur concretesubstance according to the present invention using an existing plant, sothat increase in cost can be suppressed.

Modified sulfur concrete substance products manufactured by the modifiedsulfur concrete substance producing method and the producing apparatusof the present invention can be used in various industries and usefields. Examples of the products include a Hume pipe, a pipe, a manhole,a propellant pipe, an oval pipe, a segment, a box culvert, an U-shapedgutter, side gutter, a cover, a three-sided water channel, a box, asidewalk/road boundary block, a curbstone, an L-shaped retaining wall, aflat plate, a fish bed block, a fish bank, a wave dissipating block, abase block, and the like.

It should also be understood that many modifications and variations ofthe described embodiments of the invention will occur to a person havingan ordinary skill in the art without departing from the spirit and scopeof the present invention as claimed in the appended claims.

1. A modified sulfur concrete substance producing method, comprising:storing a sulfur-containing material in a melt state in a materialhopper heated to a temperature within a preset temperature range ofwhich a lower limit is equal to or above a melting point of sulfur;pulling the sulfur-containing material out of the material hopper, usinga pressure generator, and into a cylinder heated to a temperature withinthe preset temperature range; pushing the sulfur-containing material outfrom the cylinder under predetermined pressure applied by the pressuregenerator and injecting the material from an injection port into a moldhaving therein a cavity which can be hermetically sealed and the moldbeing heated to a temperature within the preset temperature range;closing the injection port of the mold after the sulfur-containingmaterial is fully injected in the cavity; slowly cooling thesulfur-containing material injected in the cavity by stopping heating ofthe mold; and taking out a modified sulfur concrete substance formed bycooling and solidifying the sulfur-containing material in the cavityfrom the mold.
 2. The modified sulfur concrete substance producingmethod according to claim 1, wherein the sulfur-containing materialstored in the material hopper is agitated by an agitating blade providedin the material hopper.
 3. The modified sulfur concrete substanceproducing method according to claim 1, wherein said injecting thesulfur-containing material into the mold includes injecting thesulfur-containing material while applying vibration to the mold.